Method and apparatus for controlling a light signal in electrophotographic recording apparatus

ABSTRACT

An optical signal control process and circuit providing an improved electronic photography method reproduction apparatus. The reproduction apparatus has a data transmitting unit converting data to be printed to a series of video data in accordance with a first clock signal and transmitting the converted video data in response to a horizontal synchronization signal applied with a predetermined time interval, and a printing control unit for controlling a mechanism used to print the video data by sending electrical signals, providing beam data used to switch the light generation of a light source element controlled by chopped chopping video data applied to the light source element, and generating the horizontal synchronization signal on the basis of a beam detection signal produced by the light source element. A chopping unit is connected between the data transmitting unit and the printing control unit, for chopping the converted video data output from the data transmitting means in response to a second clock signal and for providing the chopped data as the chopping video data. Accordingly, the chopped video data is transmitted as beam data by the printing control unit and is then used to control the amount of light exposed on the photosensitive drum. The amount of the light is controlled optimally by the variable selection of the frequency of the second clock signal.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application makes reference to, incorporates herein andclaims all benefits accruing under 35 U.S.C. §119 from our applicationearlier filed in the Korean Industrial Property Office on May 31, 1993of our application entitled Method and Apparatus for Controlling a LightSignal in Electrophotographic Developing Type Printer, which applicationwas duly assigned Ser. No. 9481/1993.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to an electrophotographicrecording, and more particularly to an apparatus and method forselectively controlling the amount of light exposed onto aphotosensitive drum without being controlled by a developing unit whenthe apparatus prints printing information.

[0003] Generally, the art of printing using an electrophotographicdeveloping technique is well known as xerography. The apparatus whethera laser beam printer, facsimile or photocopier, as its basic principle,utilizes an adhesive force of static electricity and an opticallyconductive semi-conductor with differences in electricity conductingrates controlled according to exposure to the light. Among theseprinters, the laser beam printer is a printing device that uses a laserdiode as its light source instead of a special fluorescent lamp or amercury lamp, and prints the printing data provided as, for example,video data for a source such as a computer, etc., on a printable mediumsuch as individual sheets of printing paper, instead of merelyreproducing images reflected from a document. As described above,recently developed laser printers, in comparison with the conventionalimpact printers that print letters by using hammers striking a platen,have a higher printing speed, lower noise level, and form finer shapesof printed letters. Also, they are very popular and widely used becausethey are easily linked with computers to receive signals conveyinginformation to be printed such as a text signal of a video signal.

[0004] The printing process of such laser beam printers includes adeveloping stage where a toner used as a developing material isattracted to a latent image formed on the photosensitive drum byexposure of the photosensitive drum to light, a transferring stage wherethe toner attracted to the drum is transferred to a printable mediumsuch as a sheet of paper fed by a feed roller, and a fusing stage wherethe toner that had been transferred onto the printable medium is fusedis then fused onto the printable medium. These stages of the processalso are generally known in the current art.

[0005] In the printing process mentioned above, it is the developingstage that is closely related to a consumption of the toner, and thatdirectly affects the printing quality. Moreover, in order for aconventional printer to control the printing density, the bias voltageof a developer is changed to adjust the amount of the toner developed.See, by way of further explanation, the IMAGE FORMING APPARATUSCOMPRISING MEANS FOR SETTING A PROPER BUS VOLTAGE OF LASER EMITTINGMEANS AND METHOD THEREFORE by S. Ogino, et al, U.S. Pat. No. 5,061,949.In one contemporary approach to control printing density, a printcontrol unit controls printing of video data with electrical signals andsupplies beam data, used during scanning of an image onto thecircumstantial exterior surface of the drum with a beam of light emittedby the light source element video data signal. This may be seen in forexample, the PICTURE REPRODUCING APPARATUS of M. Yamamoto, et al., U.S.Pat. No. 3,894,182. Also, the print control unit receives beam detectionsignals generated by the light source element and supplies a horizontalsynchronization signal and a bias voltage control signal to a biasvoltage generator that provides the bias voltage to the developer.

[0006] The amount of toner attached on the drum during the developingstage is determined by the bias voltage and the intensity of the biasvoltage is controlled by an adjusting terminal known as a printingdensity selecting switch, installed on the control panel in an externalstage of the printer. A printer using this approach to control ofprinting density is very inconvenient to use however, because theprinting density has to be adjusted for each use. Moreover, thisapproach requires intense, uninterrupted concentration from the user.Also, it is very hard for unskilled users to accurately and repeatedlyadjust the adjustment terminal. Frequently, the durability of thephotosensitive drum in such laser printer is shortened and the tonerconsumption is increased when the user fails to adjust the bias voltageproperly.

SUMMARY OF THE INVENTION

[0007] Accordingly, it is an object of the present invention to providean improved printing process and apparatus.

[0008] It is another object to provide a method and apparatus forselectively controlling the amount of light illuminating thephotosensitive drum without controlling the developing unit when animage is printed with a laser beam being used as a light signal.

[0009] It is a further object to provide a laser reproduction processand printer offering an optimum printing quality by automatically,internally selecting the amount of light illuminating the photosensitivedrum.

[0010] It is a still further object to provide a laser printing processand printer having a simple circuit externally adjusting the sharpnessof characters, symbols, and graphs to be printed during the process.

[0011] It is a yet further object to provide a process and controlcircuit for reliably controlling toner consumption in anelectrophotographic developer.

[0012] It is a still yet further object to enable a user of anelectrophotographic developer type printer to transmit to a printer datacontrolling print quality while transmitting data defining the images tobe printed by the printer.

[0013] These and other objects mentioned above, may be achievedaccording to the principles of the present invention with a process andan apparatus using a data transmitting unit converting video data inresponse to a horizontal synchronization signal applied with apredetermined time interval by converting data to be printed into aseries of lines of serial video data in accordance with a first clocksignal, and a printing control unit regulating a mechanism used to printthe video data by generating electrical signals representing the videodata, providing beam data used to switch the generation of lightprovided by a light source element that had been obtained from choppedvideo data applied to the light source element, and generating ahorizontal synchronization signal by processing a beam detection signalproduced by the light source element. A chopping unit connected betweenthe data transmitting unit and the printing control unit chops theconverted video data received from the data transmitting unit inresponse to a second clock signal, and provides the chopped video data.

[0014] According to the present invention, printing may be performed byconverting data to be printed into a series of lines of video data inaccordance with a first clock signal and transmitting the convertedvideo data in response to a horizontal synchronization signal exhibitinga predetermined time interval. Chopped video data is generated bychopping the converted video data in response to a second clock signal;and beam data obtained from the chopped video data is supplied forcontrolling the light generation of a light source element. Thehorizontal synchronization signal is operated by processing a beamdetection signal resulting from the beam of light produced by the lightsource element.

[0015] In the practice of the present invention, the frequency of thefirst clock signal is set to be either equal to or lower than thefrequency of the second clock signal. If the frequency ratio between thefirst and second clock signals is an integer multiple, a single dividerstage may be used; the first and second clock signals should then begenerated from different output terminals of the divider stage.

[0016] According to the configuration and method of the presentinvention, the chopped video data is generated by the printing controlunit as beam data, and is then used for controlling the amount of lightilluminating the photosensitive drum. The amount of the light isoptimally controlled by selecting the second clock signal. Therefore,the user can adjust the density of printed images by designating orselecting the data defining the amount of light exposed by means ofsoftware. By doing so, the sharpness of the printed images can be easilyadjusted without adjusting the bias voltage of a developing unit.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] A more complete appreciation of this invention, and many of theattendant advantages thereof, will be readily apparent as the samebecomes better understood by reference to the following detaileddescription when considered in conjunction with the accompanyingdrawings in which like reference symbols indicate the same or similarcomponents, wherein:

[0018]FIG. 1 is a block diagram used to provide an abstractrepresentation showing a simplification of a typical electrophotographicdeveloping type printing process.

[0019]FIGS. 2A to 2D are exemplary timing charts illustrating waveformsto explain an operation of the process represented by FIG. 1.

[0020]FIG. 3 is a block diagram illustrating an apparatus forcontrolling the light signal in an embodiment constructed according tothe principles of the present invention.

[0021]FIGS. 4A to 4G are timing charts illustrating waveforms of signalsoccurring at corresponding stages in the circuit shown in FIG. 3.

[0022]FIG. 5 is a graph illustrating a comparison of voltage potentialon the photosensitive drum for an embodiment of the present inventionand for an exemplary embodiment of prior art.

DETAILED DESCRIPTION OF THE INVENTION

[0023] In contemporary printing processes described earlier herein, thedeveloping stage that is closely related to consumption of the toner,and therefore directly affects the printing quality. Moreover, in orderfor a conventional reproduction apparatus to control the printingdensity, the bias voltage of the developer is typically changed incontemporary printers in order to adjust the amount of the tonerconsumed. Referring now to FIG. 1, a diagram illustrating an exemplaryconventional technique for accomplishing printing control is shown in anabstract representation to facilitate an understanding of the principlesof the present invention. As shown in FIG. 1, data transmitting unit 10receives printing data supplied from data output device 1 of a sourcesuch as a computer having a RIP (Raster Image Processor), via a bus line2. Also, transmitting unit 10 converts the print data to a series oflines of video data in correspondence with a clock signal fed in via aline 52 and then, outputs the converted video data via line 12 inresponse to a horizontal synchronization signal exhibiting apredetermined time interval applied via a line 14. Data transmittingunit 10 contains a shift register type of memory element. A printingcontrol unit 20 controls a mechanism required for printing the videodata with electrical signals and supplies beam data, used to switch thelight generation of a light source element located in a beam scanningunit 30, to the light source element through a line 22 by obtaining thebeam data via a line 12 from the video data received. Also, printcontrol unit 20 receives beam detection signals generated by the lightsource element 6B for processing via a line 24 and then, supplies thehorizontal synchronization signal to the line 14. In addition, theprinting control unit 20 supplies a bias voltage control signal via aline 72 to a bias voltage generator 70. Thus, the bias voltage generator70 provides a bias voltage to the developer not illustrated.

[0024] The beam scanning unit 30 is switched over according the beamdata provided on the line 22 to generate the laser beam to be scannedupon the photosensitive, uniformly changed circumferential surface ofthe drum. Also, beam scanning unit 30, in response to the beamgenerated, sends beam detection signals to a line 24. A clock signalgenerator 40 supplies a basic clock signal of system to a dividing unit50 via a line 42. The dividing unit 50 divides the basic clock signalinto a certain ratio and then supplies the divided clock signal to thedata transmitting unit 10 via a line 52 as the clock signal.

[0025] The timing relationship of waves output from each stage mentionedabove is illustrated in FIGS. 2A to 2D. Referring to FIGS. 2A to 2D, ifan assumption that FIG. 2A is a waveform of the line 42, FIG. 2B is awaveform of the line 52, and FIG. 2C is a waveform of the line 12, ismade, FIG. 2D is output from the line 22. As illustrated by the examplesgiven here, one dot is printed on an interval T1 in the waveform of FIG.2C as black and another dot is printed on an interval T2 as white (e.g.,as by not applying toner to the corresponding spot on the photosensitivedrum). During interval T3, two dots are printed as black (i.e.,successive dots of toner are fixed to the printed medium passing throughthe reproduction apparatus).

[0026] Referring again to FIG. 1, the light source element in the beamscanning unit 30 emits light according to the waveform of FIG. 2D thatis fed in via the line 22 and the beam scanning unit 30 scans theemitted laser beam onto the photosensitive drum. Therefore, thedeveloping stage is implemented. Note that the amount of toner attachedon the drum during the developing stage is determined by the biasvoltage of the bias voltage generating unit 70 that generates the biasvoltage in response to the bias voltage control signal on the line 72.The generating unit 70 is has a circuit element capable of outputting ahigh-voltage and an adjusting terminal used for adjusting the voltageexternally. Where, the bias voltage control signal on the line 72 is asignal to switch a generation of the bias voltage, substantially theintensity of the bias voltage is controlled by the adjusting terminalinstalled in external stage of the printer. The adjusting terminal iswell known as a printing density selecting switch on the control panel.Thus, such control of the bias voltage in the developing unit isgenerally known in the art. For example, where the surface of thephotosensitive drum has a voltage potential of −600 volts on charging,and has a voltage potential of −50 volts on exposing, the bias voltageadjusted as −500 volts provides a higher printing density in comparisonwith the bias voltage adjusted as −400 volts.

[0027] This reproduction apparatus is very inconvenient to use becausethe printing density has to be adjusted for each use. Furthermore, doingso requires a great concentration from the users. Also, it is very hardfor the unskilled users to adjust the adjustment terminal. Frequently,the durability of the photosensitive drum in such laser printer isshortened and the toner consumption is increased when failing to adjustbias voltage properly.

[0028] In the following paragraphs, a light signal controlling apparatusconstructed as preferred embodiments in accordance with the principlesof the present invention will be described. To provide a more thoroughunderstanding of the present invention, the detailed description onthese circuits is given. Those skilled in the art however, will clearlyrecognize that the present invention can be implemented withoutunnecessarily detailed descriptions. Also, well known circuitcharacteristics and its functions are not explained in detail so as notto obscure an embodiment of the present invention. Further, the stagesthat are the same or similar to those of the conventional techniquesdescribed previously will be assigned with the same reference numerals.

[0029] Referring now to FIG. 3 where an illustration explaining thepreferred embodiments of the present invention is given, datatransmitting unit 10 receives the video data to be printed via data busline 2 and converts the data received into serial of video dataaccording to the first clock signal provided via a line 52 and, byresponding to the horizontal synchronization signal exhibiting apredetermined time interval that is fed in on line 14, transmits theconverted video data through line 12. A printing control unit 20controls the mechanism required for printing the video data by means ofelectrical signals and provides the beam data used to switch the lightgeneration of light source element 68 located in the beam scanning unit30 to the light source element via a line 32 to emit light beam 90. Thebeam data is obtained from the chopped video data fed in via a line 102.Also the printing control unit 20 receives and processes the beamdetection signals generated by the light source element through a line34, and provides via line 14 the horizontal synchronization signalgenerated by processing the beam detection signals. Note that theprinting control unit 20 is generally called an engine control unit.Also, for the light source element, a semiconductor laser capable ofproducing 0.6 milli-Watts is used.

[0030] A chopping unit 100 is preferably constructed using an logicstage such as an AND gate having one input port coupled to receiveserial video data via lead 12 from data transmitting unit 10 and asecond input port coupled to receive the second clock signal via lead62; the output port of the logic stage such as an AND gate would becoupled to printing control unit 20. During operation of the choppingunit 100, the data generated by chopping the converted video dataapplied through lead 12 in response to the second clock signal fed invia a lead 62, is provided to lead 102 as the chopped video data. Here,the term “chopped” means that the video data is divided according to thesecond clock signal. This is carried out by gating of the AND gate withthe second clock signal.

[0031] A clock signal generator 40 generates local, or basic, clocksignals and then, applies these clock signals to a lead 42. A firstdivider 50 divides the basic clock signals with a certain dividing ratioand, then provides the first clock signal to lead 52. A second divider60 divides the basic clock signal according to dividing ratio datacomponent of the video data received via lead 2, separated from thevideo data through output port 5 and fed in through a line 3 and then,provides the second clock signal on a line 62, where, the second divider60 may have a PWM function. An output port 5 is connected between thedata bus line 2 and the line 3, and stores the dividing ratio data.Here, line 2 is normally made up of sixteen bits or thirty-two bits, andline 3, eight bits. That is, the data output device 1 such as a computerconnected through the line 2, provides designated dividing ratio data asa component of the video data signal transmitted via lead 2, inaccordance with the selection by the user and the printing data.

[0032] After assuming that the dividing ratio data is designated via thedata output device 1, is referring to FIGS. 4A to 4G with anillustration describing the chopping operation carried out by thechopping unit 100, a waveform of FIG. 4E is output on the output line102 of the chopping unit 100 if an assumption that waveforms of FIGS.4A, 4B, 4C, and 4D are output respectively on the line 42, the line 52,the line 12, and the line 62 in FIG. 3 is given. Intervals C1, C2, andC3 in the waveform of FIG. 4C are the same as those of T1, T2, and T3 inFIG. 2. Note that the number of high pulses as shown in the intervalsE1, E3 in the waveform of FIG. 4E will be larger than the number ofpulses in the waveform of FIG. 4C. Also, the waveform of FIG. 4E ischanged to the waveform of FIG. 4G in case the waveform of FIG. 4Dchanges to a waveform of FIG. 4F. That is, if the frequency of thesecond clock signal provided by second divider 60 to line 62 is changedby a user applying video data via lead 2 containing a dividing ratiocomponent that is greater by a factor of two than the dividing ratiothat was applied to second divider 60 to produce the second clock signalwith the pulse frequency shown in FIG. 4D, the frequency of the secondclock signal will be correspondingly changed to provide the waveformillustrated in FIG. 4F exhibiting a pulse frequency twice that of thesecond clock signal waveform illustrated in FIG. 4D; concomitantly, thefrequency of the chopped video data transmitted by chopping unit 102 vialine 102 also changes by a factor of two, as is illustrated by withwaveform of FIG. 4G.

[0033] Accordingly, the printing control unit 20 inputs the choppedvideo data through the line 102 and then, printing control unit 20outputs the beam data for switching the light source element throughline 32. Here, the beam data is almost the same as that on line 102. Inresponse is to this data, light source element 68 in beam scanning unit30 lights up to generate laser beam 90. Laser beam 90 generated by lightsource element 68 has a wavelength of 650 to 800 nM, generally.

[0034] Also, the faster the second clock signal operates the greater thenumber of chopping operations occur. As a result, the effective amountof light illuminating the photosensitive drum decreases. On thecontrary, when the user designates a smaller dividing ratio data byusing softwear (e.g., abstractly represented by mode selector 66) tospecify the dividing ratio component of the video data transmitted viadata bus 2 in order to lower the frequency of the second clock signal(i.e., to set the second frequency to a lower value), the chopped videodata transmitted via line 102 has a lower pulse frequency andconsequently, the amount of light emitted by source 68 increases.Accordingly, the amount of light to which each point on thephotosensitive surface of the drum is exposed is increased and thus, thedensity of the toner is increased. In this manner, printing quality,that is, the sharpness of printed images, is determined by changing theamount of toner attached during the developing process according to thechange in the amount of light emitted by light source 68 of beamscanning unit 30, and thus, the amount of light illuminating theexterior circumferential surface of the photosensitive drum.

[0035] It is widely known that the amount of light illuminating thephotosensitive drum is proportional to the light output of laser source68 and that an exposure time per one dot of laser beam, and is inverselyproportional to the optical area per one dot of the laser beam. Here,referring to FIG. 5, the pulse G2 represents the chopping effect inaccordance with the present invention. In pulse G2, the voltagepotential on the photosensitive drum is less than the voltage potentialacross the same photosensitive drum with the prior art of pulse G1 byabout 50 volts. In FIG. 5, the intervals EA and NEA represents theexposed area and the unexposed area on the photosensitive drum,respectively. Therefore, the amount of toner attracted to the drumdecreases since the voltage potential is lowered by chopping unit 100.

[0036] So far, the present invention has been explained with thedrawings attached and examples given. It should be clear to thosefamiliar with this field that several changes and modifications on theinvention are possible if they are implemented within the scope of thetechniques utilized in the present invention.

What is claimed is:
 1. An electrophotographic developing typereproduction apparatus, comprising: data transmitting means forgenerating converted data by converting input data to be printed intovideo data in accordance with a first clock signal, and for transmittingthe converted data in response to a horizontal synchronization signalexhibiting a predetermined time interval; chopping means for providingchopped data by dividing the converted data from said data transmittingmeans in accordance with a second clock signal; and printing controlmeans for providing beam data in response to said chopped data, forcontrolling printing of the video data by generating electrical signalsto control generation of a light beam by a light source element, and forgenerating said horizontal synchronization signal in correspondence witha beam detection signal derived from the light beam by the light sourceelement.
 2. The electrophotographic developing type reproductionapparatus of claim 1, further comprised of the second clock signalhaving a frequency greater than the first clock signal.
 3. Theelectrophotographic developing type reproduction apparatus of claim 1,further comprised of a frequency of the second clock signal being aninteger multiple of a frequency of the first clock signal.
 4. Theelectrophotographic developing type reproduction apparatus of in claim1, further comprised of said chopping means comprising an AND gatehaving a first input port coupled to receive said converted data and asecond input port coupled to received said second clock signal.
 5. Theelectrophotographic developing type reproduction apparatus of claim 1,further comprised of mode selecting means enabling a user to externallychange a characteristic of said second clock signal.
 6. Theelectrophotographic developing type reproduction apparatus of claim 1,further comprised of a semiconductor laser device serving as the sourceelement.
 7. The electrophotographic developing type reproductionapparatus of claim 1, comprised of: first means for generating a localclock signal; and second means for generating said second clock signalby dividing said local clock signal in dependence upon a dividing ratiocomponent of said input data.
 8. The electrophotographic developing typereproduction apparatus of claim 1, comprised of: means for generating alocal clock signal; first means for generating said first clock signalby dividing said local clock signal; and second means for generatingsaid second clock signal by dividing said local clock signal independence upon a dividing ratio component of said input data.
 9. Theelectrophotographic developing type reproduction apparatus of claim 1,comprised of said chopping means intermittently transmitting said serialvideo data during pulses of said second clock signal.
 10. Theelectrophotographic developing type reproduction apparatus of claim 1,comprised of: a component of said input data specifying a dividingratio; and means for setting a frequency exhibited by said second clocksignal in dependence upon said component.
 11. The electrophotographicdeveloping type reproduction apparatus of claim 1, comprising: acomponent of said input data specifying a dividing ratio; means forsetting a frequency exhibited by said second clock signal in dependenceupon said component; and said chopping means dividing said converteddata into a series of pulses exhibiting a pulse frequency correspondingto said frequency exhibited by said second clock signal.
 12. A methodfor controlling a light signal in an electrophotographic developing typereproduction apparatus, said method comprising the steps of: generatingconverted data by converting input data to be printed into video data,in accordance with a first clock signal, and for transmitting theconverted video data in response to a horizontal synchronization signalexhibiting a predetermined time interval; generating chopped data bydividing the converted data in dependence upon a second clock signal;supplying beam data for controlling generation of said light signal by alight source element in response to said chopped data; and generatingsaid horizontal synchronization signal in dependence upon a beamdetection signal obtained from said light signal.
 13. The method ofclaim 12, comprising the second clock signal having a frequency higherthan the first clock signal.
 14. The method of claim 12, comprising afrequency of the second clock signal being an integer multiple of afrequency of the first clock signal.
 15. The method of claim 12,comprised of generating the chopped data by applying the converted datato a first input port of an AND gate data and applying the second clocksignal to a second input port of the AND gate.
 16. The method of claim15, comprised of changing a characteristic of the second clock signal inresponse to a selection made by a user of the reproduction apparatus.18. An apparatus for printing video data, comprising: data bus means forproviding input video data and for providing dividing ratio data; clocksignal generating means for generating a first clock signal and forgenerating a second clock signal, said second clock signal exhibiting acharacteristic depending upon said dividing ratio data; datatransmitting means for converting said input video data into serialvideo data in response to said first clock signal, and for transmittingsaid serial video data in response to a horizontal synchronizationsignal; logic means for providing chopped video data in dependance uponsaid serial video data and said second clock signal; printing controlmeans for generating beam data in response to said chopped video data;and beam scanning means for providing a laser beam for defining imagescorresponding to said beam data and for generating a beam detectionsignal derived from scanning of said laser beam; said printing controlmeans generating said horizontal synchronizing signal in dependence uponsaid beam detection signal.
 19. The apparatus of claim 18, comprised ofgenerating said first clock signal with a frequency less than saidsecond clock signal.
 20. The apparatus of claim 18, comprised ofgenerating said first clock signal with a frequency equal to said secondclock signal.
 21. The apparatus of claim 18, comprised of said clocksignal generating means comprising means for changing saidcharacteristic of said second clock signal in correspondence withchanges in said dividing ratio data.
 22. The apparatus of claim 18,comprised of said clock signal generating means comprising: first meansfor generating a local clock signal; and second means for generatingsaid second clock signal by dividing a frequency of said local clocksignal in dependence upon said dividing ratio data.
 23. The apparatus ofclaim 18, comprised of said clock signal generating means comprising:means for generating a local clock signal exhibiting a first pluralityof pulses characterized by a local frequency; first means for generatingsaid first clock signal by dividing pulses of said local clock signal toprovide a second plurality of pulses characterized by a secondfrequency; and second means for generating said second clock signal bydividing said pulses of said said local clock signal in dependence uponsaid dividing ratio data, to provide a third plurality of pulsescharacterized by a third frequency established in dependence upon saiddividing ratio data.